How to create email domain alias?

When I create account domain.com and setup some mailboxes in them, how I can create alias domain.ru for this account in cPannel?
Before I have qmail + vpopmail, in them I ceate domain.com and then add with vaddaliasdomain domain.ru... After that I can add mailboxes only in domain.com and they all work for damoin.ru too. Can I do this in cPanel?
/sorry for my Engleash %-)/